Solid-phase synthetic techniques, in which a reagent is immobilized on a polymeric material which is inert to the reagents and reaction conditions employed, as well as being insoluble in the media used, are important tools for preparing amides, peptides and hydroxamic acids. For solid phase peptide synthesis, a summary of the many techniques may be found in J. M. Stewart and J. D. Young, Solid Phase Peptide Synthesis, 2nd. Ed., Pierce Chemical Co. (Chicago, Ill., 1984); J. Meienhofer, Hormonal Proteins and Peptides, vol. 2, p. 46, Academic Press (New York), 1973; and E. Atherton and R. C. Sheppard, Solid Phase Peptide Synthesis: A Practical Approach, IRL Press at Oxford University Press (Oxford, 1989). For the use of solid phase methodology in the preparation of non-peptide molecules see Leznoff, C. C., Acc. Chem. Res., 11, 327-333 (1978).
A number of polymeric reagents have found synthetic use in simple functional group transformations. See A. Akelalh and D. C. Sherrington, Application of Functionalized Polymers in Organic Synthesis, Chem Rev., 81, 557-587 (1981) and W. T. Ford and E. C. Blossey, Polymer Supported Reagents, Polymer supported Catalysts, and Polymer Supported Coupling Reactions, in Preparative Chemistry using Supported Reagents, Pierre Laszlo, ed., Academic Press, Inc., 193-212 (1987). For the use of polymeric reagents in oxidation reactions see J. M. J. Frechet et al., J. Org. Chem., 43, 2618 (1978) and G. Cainelli et al., J. Am. Chem. Soc., 98, 6737 (1976). For the use of polymeric reagents in halogenation reactions see J. M. J. Frechet et al., J. Macromol. Sci. Chem., A-11, 507 (1977) and D. C. Sherrington et al., Eur. Polym. J., 13, 73, (1977). For the use of polymeric reagents in epoxidation reactions see J. M. J. Frechet et al., Macromolecules, 8, 130 (1975) and C. R. Harrison et al., J. Chem. Soc. Chem. Commun., 1009 (1974). For the use of polymeric reagents in acylation reactions see M. B. Shambhu et al., Tet. Lett., 1627 (1973) and M. B. Shambhu et al., J. Chem. Soc. Chem. Commun., 619 (1974). For the use of polymeric reagents in Wittig reactions see S. V. McKinley et al., J. Chem. Soc. Chem. Commun., 134 (1972).
Polymeric reagents have also found widespread use in combinatorial synthesis and for preparing combinatorial libraries. See F. Balkenhohl et al., Angew. Chem. Int. Ed. Engl., 35, 2288-2337 (1996) and L. A. Thompson et al., Chem Rev., 96, 555-600 (1996).
A polymeric reagent has the advantage of ease of separation from low molecular weight reactants or products by filtration or selective precipitation. The polymeric reagent can also be used in excess to effect fast and quantitative reactions such as in the case of acylations, or a large excess of reactants may be used to drive the equilibrium of the reaction towards product formation to provide essentially quantitative conversion to product, as see in solid phase peptide synthesis. A further advantage of supported reagents and catalysts is the fact that they are recyclable and that they lend easily to automated processes. In addition, supported analogs of toxic and odorous reagents are safer to use.
PCT application publication no. WO96/26223 discloses the synthesis of hydroxamic acid compounds using a solid phase hydroxylamine substrate.
Prasad et al. disclose a O-methylhydroxylamine-polystyrene resin compound in J. Steroid Biochem., 18, 257-261 (1983).
Resin-bound Weinreb-like amides are disclosed by Fehrentz et al., Tet. Lett., 1995, 36, 7871-7874 and Dinh et al., Tet. Lett., 1996, 37, 1161-1164.
Polymeric Horner-Wadsworth-Emmons reagents are disclosed by Wipf et al., J. Org. Chem., 1997, 62, 1586 and Johnson et al., Tetrahedron Lett., 1995, 36, 9253.